Two piece cartridge and method of making same



sept. v3o, 1958 E. F. STEALEY 2,853,945

TWO yPIECE! CARTRIDGEAND METHOD OF' MAKING SAME Filed May 27, 1955 BEFORE FIR/N6 BEFORE FIR/NG AFTER FIR/NG Il 2a INVENTOR.

EVERETT F. STEALEY TWO PIECE vCARTRIDGE MEllI-IODF MAKING SAME' v Everett F. -Stealey, Cleveland, `tll'io, assignor to The Boehm "'Pressed Steel Company, Cleveland, Ohio, a corporation of Ohio This invention relates to methods andmeajns 'for making twop1ece 'steel cartridge cases and vthe objects of vthis in- Ventron arethe same as'recited in mycope'ndingI but now abandoned application Seri'ahNo. 499,648, tiled April 6, 19,5'5, lbutwith the addition vof `certain changes in construction representing an important .modification of the aforesaidpending application.

.An .important object tof ythe present invention over the pendlngapplication is 'the provision of an improved construction for connecting a wrap-around case with the base `which restrains too great anexpansion of the case under the :force of the yexploding charge 'as will-make rapid ejection yof the shell 'from the breech diicult under some conditions. IIn other words, the present connection of the case with 'the base 'offers afjoint which will Vyield toade'gree and permit 4only so lmuch case expansion as will assure a gas-'tight 'sealin the :breech under lire, and

yet will .recover or return toits original `diameter tomake certain of positive and rapid ejection, the `proof of this being evidenced 'by the yf'act'that the vcase.can be rechambered without eifort.

.Another important object is the provision of va wraparound case with a base fastening angewhich is substantially parallel ywith the axis of the shell and normal tothe adjacent 'most lyieldable free -orfspringlike portion of the ifcase, s'o 'that the juncture -of the 'flange vwith the spring-like vportion :can 'be subjected to a controlled re- .to allow vejection o'f the 'assembly ywithout separationof 4the base and case and, at the `sarne time, permitting natural orientation of the laminationscof the hange.

Like the laforesaid pending application, the,;present.in vention providesfor case expansionV and contraction of 'the laminated wrap-around 'case and .flangeby reason of a portion of the laminated "flange being supported upon vthe base `and exposed to pressures 'within the rca se with 'freedom of its flaminations to move or adjust-during vwindingV or 'unwindin'gtendencies of `the case caused by'app'lied and fres'idualstresses. The axial componentof an explodjingcharge within the vcase expands it against the breech walls and against the base to'preclude possibility of Vgas leakage from within and around the case.

AOther objects and advantages 'of the invention will become apparent duringthe course of the following description. v

In the accompanying drawing forming a 'part of the description wherein like numerals are employed to designate like lparts throughout the several views:

Figure l is a vertical section taken throughjthe'center 'of the improved base showing vthe improved case 'connected therewith;

Figure 2 is an enlarged section 'of rone side fof the joint between 'the case and base .showing rthe :relative position ofthe partspri'or to firing or exploding theshell;

Figure 3 is a similar view showingthe relative positions of the parts after firing for explosion of the shell; and

Figure 4 'is ran -enlarged section of kfone -side -of la modi- .tiedf jointy between the .case and base i'prior to iti-ring.

2,853,945 Patented Sept. 30.,` 19,58

Referring more .particularly tothe drawing, the numeral 10 designates a cylindrical body shell, or case, of low carbon steel `formed by rolling a trapezoidal `shaped sheet into cylindrical form to provide what is termed a wraparound type of cartridge case. The sheet being rolled or Wound spirally provides the case with plural coiled spring-like laminations or layers. With this type. of case, internal pressure tends Vto unwind the resilient coil formation ofthe body structure until contact'is madewith the breech wall. YIn contrast to the drawn steel case, in which the `wall of the body is subjected to hoop tension, which condition induces high stresses often exceeding the yield pointrof the material and causinglpermanent deformation, the vcoiled spring-like formation of the wrap-'around'case is subjected, `in' the main, to 'bending strains which are quickly reversed on subsidence of pressure.

' This cylindrical body shell is, of course, placed under vstrainingpressure oliered by the base locking rib sufficient .as is well understood in the art.

pressure on a mandrel to iron` the spirally disposed edges ofthe blank into a true cylindrical form without .raised portions on vthe inner and outer surfaces of the body shell This laminated end 'of the case is formed to include a rst inwardly extending conical flange portion 14 adjacent the cylindrical body wall lof the case, an intermediate flange portion 1`5 which is substantially normal to the case axis, and a second ange portion 16 substantially normal to the intermediate portion 15 and substantially parallel with the case axis. The portions 15 and 16 meet at a corner orjuncture portion 17. The resilient laminated portions 14 and 15 of the'case are supported upon the base 11 and are free to move relatively and relative theretol either in firing or in storage. These portions of the case constitute a stepped flexible flange portion which is free to expand and con.- tract radially and circumferentially and to move axially relative to the base plate.

The base plate 11 for the Acartridge case is preferably made from low cost carbon steel with a contoured face having a first conical surface 18 adjacent the periphery of the base to seat and support theA outer surface of the conical ange portion 14 of the case, a second surface -19 concentric with thev surface -18 and substantially parallel with the end surface 20 of the base to seat and support the outer surface of the intermediate ange portion 15. Spaced a substantial distance inwardly from the periphery of the base and the intermediate surface 15 and concentric therewith, the base is provided with an annular groove 21. This groove is justslightly deeper than the flange 16 is long and is slightly wider than the combined `thickness of the laminations' of 'the flange. The base plate 11 in all modifications shown herein is cold Ycoined as in my copending application Serial No. 389,774, now U. kS. Patent No. 2,818,021, to increase its physicals and 'the iinish of the entire surface of the base including ythe supporting surfaces 18 and 19. This coining compacts or compresses the fibres of the base and of the rib v25 to be presently described. The outer wall ZZfof the ,groove 21 is substantially perpendicular tothe surface` 19 .to meet the same at asubstantial right .angle corner .25 preferably having a radius ofabout one-sixteenth of an inch. The inner wall 24of this grooveextends a distancefbeyond the surface .19 to `provide one side of an annular opstanding rib 25. which is sulflcientlylargeand has .aninclined-face 26 .against which pressure is exerted rto Ydeform the rrib andwcause it to span .they groove and lsqueeze or pinch 'fthe juncture 17-oftheycase'iiange portions 15 and 16 against thefoorner 123- .to retain the liange 16 Within the groove After this deformation of the rib, it may be staked as at 30 at an angle of about forty-five degrees as shown in Figure 4 to further compress the juncture portion 17 of the case against this corner 23. Pressure exerted upon the rib in fastening the case flange within the groove 21 pinches the juncture portion 17 over the corner 23 to a degree which may cause a slight reduction in the thickness of the case laminations at this point. This may also cause the laminations of the flange 16 within the groove to angle at about five degrees, which is permitted by the groove being wider than the combined thicknesses of the flange laminations as shown in Figure 2. `If desired, the flange 16 as shown in Figure 4, instead of being formed parallel with the case axis, may be initially inclined slightly inward at about a five degree angle relative to the case axis to make it somewhat of a conical shape, but not to the extent shown in my copending application, wherein there is more of a tendency for the end conical flange to pull radially out of the groove upon firing. By extending the flange 16 parallel with the case axis, with controlled confinement of said flange within a groove of slightly greater width than flange thickness, a small amount of unwinding of the flange laminations is provided for.

Figure 4 illustrates a modification of the connection between the case 1l) and base 11 and here the parts which correspond to 'those of the preceding modifications are designated with corresponding reference numerals. The variations over the other figures are first, that the base plate of Figure 4 omits the inclined surface 18 and instead has a surface 35 which is parallel with the end face 20 to take the place of both surfaces 18 and 19 of the preceding modification. The second variation is that the case is provided with a free flange portion 15 normal to the case axis and corresponds with the portion 1S of the preceding modication.

Just exactly what changes occur in the positions of the parts at the instant of tiring is not known; but as far as can be discerned after firing the shell and sectioning or cutting the same transversely or removing a pie-shaped segment thereof, it is noted `'that the outer lamination 27 of the flange portion 14 and the intermediate lamination 28 has been driven down hard against the base 11, while the inner lamination 29 and the outer portion of the intermediate lamination 28 of the flange portions 14 and has heaved inwardly in spaced relation to the other Convolutions, probably due to the uncoling tendency of the wrap-firound case during the explosion and the recoil tendency of the case to return to normal positionimmediately after `the explosion. It is believed that this flexibilityof the case in these regions of free movement of the portions114 and 1S allows the case to literally breathe to expand tothe breech Walls under fire, or in storage,` and to retract under residual stress to return toward its original diameter for easy ejection.

It is also unknown exactly what action occurs in the flange 16 within the groove 2l at the instant of firing or applied stress. However, after firing and sectioning of the shell, itappears that there has been a relative slight slippage lengthwise between t-he laminations of the flange 16 due to their changed positions as depicted in Figure 3 and comparing it with the original positions of the parts before firing as shown in Figure 2. It is believed that while the compression of the laminations or layers between the corner 23 of the groove and the rib 25 is great at the instant of firing, nevertheless, it is possible that there is some degree of slippage between these compressed laminations; `but not anywhere near sufficient to pull the flange 16 out of its groove. Such action and construction of the joint probably allows the case to slightly unwind during firing, in varying degrees throughout its length, and permits return to a smaller diameter upon the recoil or Winding action of the case permitting orientation from actual firing tests to meet the rigid requirements of gas tightness between the case and base, rapid chambering and ejection, with no possibility of adverse effects upon the` shell from long storage.

Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of .construction and the combination and arrangement of parts may be resorted to i without departing from the spirit and Vthescope ofthe of the laminations within the confines defining the anchorinvention as hereinafter claimed.

What is claimed is:

1. A two-piece cartridge case comprising a base having a contoured inner face, `said face near its periphery provided with a conical surface and a surface normal to the axis of said base positioned radially inwardly therefrom, said contoured face inwardly of said normal surface having `an attaching groove forming with `said normalsurface a juncture corner, said base inwardly of said groove haviug adeformable rib adapted to be deformed toward said juncture corner, a tubular body shell formed from Va sheet of material forming a Wrap-around cylindrical case, said case having a first inwardly directed conical flange portion unattached to and supported upon said conical surface, said first flangeportion having a secondflange portion normal to the shell axis unattached to and supported on said normal surface of said base and exposed to an exploding charge within said shell, said conical and normal flange portions being free to.move.relative to said base, said second flange portion terminating in a flange parallelfwith the axis of said shell and having its `juncture portion with said normalportion of said second flange portion confined between said juncture cornerand said deformable rib, said terminal flange portion parallel with the axis of said shellbeing loosely received in said attaching groove, andthe inner lamination of saidsecond flange portion at its conical and normal portions being free to move relative to its other laminations to compensate for strains resulting from residual and` applied stresses.

2. A two-piece cartridge case comprising` a base having a face near its peripheryprovided with a supporting` surface substantially normal to the axis of said base, said face having spaced a substantial distance inwardly` of its periphery an attaching groove forming with said surface a juncture corner, said base inwardly of said groove having a deformable rib adapted to be deformed toward said corner, a cylindrical body shell formed of plural spirally coiled resilient laminations, said shell having an end formed into a flanged portion with plural spirally coiled resilient laminations and having a first section adjacent said shell body substantially normal to said shell axis supported unattached upon said supporting surface of said base and exposed to the exploding charge of said shell and free to move relative to said base, said flange portion having a second section substantially parallel to said shell axis andhaving its juncture with said normal portion of said flange portion pinched between said juncture corner and said deformable rib, said second section of said flange portion being loosely received in said attaching groove, said flange portion being secured to said 'base only at said juncture corner, and said laminations of said flange portion being free to move relatively upon coiling and uncoiling tendencies of said body shell.

3, A two-piece cartridge case comprising a base having a supporting surface substantially normal to the axis of said base and having spaced a substantial distance inwardly of its periphery an attaching groove having side walls substantially parallel with the axis of said base, one of said side walls forming with said surface arjuncture corner, the other of said side walls being extended axially beyond said surface to form a deformablerib opposite said juncture corner, a cylindrical body shell formed of plural spirally coiled resilient laminations, said shell having an end formed into an inwardly extending flanged portion with plural resilient laminations and having a rst section adjacent said body shell substantially normal to said shell axis supported unattached upon said supporting surface of said base and free to move relative to said base, said flange portion having a second section substantially parallel to said shell axis and having its juncture with said rst section arranged upon said juncture corner, said deformable rib being deformed toward said corner to pinch said juncture portion of said ange between said rib and said juncture corner, said second section of said ange portion being loosely received in said attaching groove, and said laminations of said first section of said ange portion being free to move relatively upon winding and unwinding of said coiled laminations of said body shell.

4. A two-piece cartridge case comprising a base, a body shell formed of a plurality of spirally coiled resilient laminations, said body shell having an end formed into a flange portion extending axially inwardly towards the shell axis and engaging said base and a second and terminal ange portion extending substantially axially and towards said base, said base having an annular recess in which the second ange portion of the body shell is loosely received, the radially outer wall of said recess forming a juncture corner in said base, said base having a deformable annular rib pressed generally radially outwardly in the cartridge case to retain the shell laminations in tight association with each other only at a pressure zone formed by a portion of the annular rib pressing a section of the body shell ange against the juncture corner ofthe base,

5. A two-piece cartridge case comprising a base, a body shell formed of a plurality of coiled relatively movable laminations, said shell having an end formed into a. rst ange portion extending substantially normal to the shell axis but supported on said base, anda second and terminal flange portion extending substantially parallel to the shell axis and towards said base, said base having an annular recess in which the second iiange portion of the body shell is received, the radially outer wall of said recess forming a juncture corner in said base, said base having a rib forcing said body shell laminations into tight association with each other and against the juncture corner of the base, the remainder of said rst and second flange portions being unattached and free for relative movement and said rst flange portion is free for axial movement away from said base whereby axial extraction forces applied to said base exert contractive forces on the convolutions of said body shell and may pull said rst flange portion away from said base.

References Cited in the tile of this patent FOREIGN PATENTS 20,897 Great Britain Dec. 20, 1890 81,680 Germany July 1, 1895 213,678 Germany Sept. 28, 1909 113,813 Great Britain Mar. 4, 1918 49,937 Norway Aug. 24, 1921 94,500 Austria Oct. 10, 1923 401,940 Italy Feb. 10, 1943 436,936 Italy June 18, 1948 

